I know this is probably a bit of a nube question, but I need some input.
So if I use
last I can see my IP, and it's also in my auth log whether failed or accepted, eg.
Dec 9 19:30:16 wilhelm sshd: Failed password for root from 22.214.171.124 port 16257 ssh2
I want to know whether it is possible to only allow connections from IP's from a certain ISP. e.g. if I do whois X.X.X.X on my IP and grep for ISP:
root@wilhelm:~# whois X.X.X.X|grep <ISPNAME> netname: <ISPNAME>
So is it possible to add this to pam for SSH connections? Are there any disadvantages to this approach(except being locked out when in another location(portknocking maybe))? It's on a VPS so I'm not worried about internet dropping out. I can just use VNC if I absolutely have to. I have done a few quick searches on this and I'll continue to.